Summary
RBB investment and deployment will require familiarity with a wide range of technical subjects. New technology creates new businesses. Fiber optics, noise-mitigation techniques, MPEG, and advanced data networking techniques such as multicast have made residential broadband technically feasible. Table 2-11 summarizes the technical foundations of RBB covered in this chapter.
With the wide perspective on market drivers and technology established in the first two chapters of this book, the following chapters turn to a more in-depth consideration of particular kinds of networks and their implications for residential broadband. In each case, technical, financial, regulatory, and market obstacles and facilitators of the networks will be considered. Cable networks are covered in more detail in Chapter 3.
| Technology | Factors Supporting Use in RBB | Factors Challenging Use in RBB |
|---|---|---|
| Metal Wire Transmission | Is an entrenched, widely employed infrastructure. | Has high-frequency transmission on metal wire that is especially subject to impairments. Uses metal wire, which is prone to external impairments that cause noise. |
| Modulation Schemes | Is a required aspect of communications; a number of robust, well-established, well-understood techniques exist. | Uses multiple modulation schemes; relative lack of standardization limits interoperability and raises costs. |
| Noise-Mitigation Techniques | Combats the effects of ingress and burst noise, without incurring a round-trip delay. Is viewed as a required aspect of communications. | Creates delay. Requires compute power and buffering. |
| Fiber Optic Transmission | In comparison with metal wire transmission: increases bit rate; covers greater distance without amplification or regeneration of signal; lowers maintenance cost; requires less space; requires less weight; safer to handle. Is immune to eavesdropping. |
Has unique impairments of its own: microfissures; difficulties in handling; incapability to be bent like wire; precise alignment of lasers required.
Uses laser transceivers, which are more expensive than electrical counterparts. Is immune to eavesdropping. |
| Signaling |
Is a required aspect of communications.
Uses connectionless protocols, such as IP, which minimize signaling burdens and promote scalability. Works with packet networks in telephone systems, which enable faster signaling than previously possible. | Is time-consuming and imposes a processing burden on communications software. Can be the bottleneck that restricts bandwidth through networks. |
| IP Multicast | Enables broadcast of data and video over wired networks. Is an important scaling technique for Internet because it reduces signaling and packet replication. |
Uses complex software, requiring the cooperation of client systems.
Uses complex accounting and security. Uses scaling that is difficult for multiple sources of multicasts. Is not widely deployed by Internet service providers. |
| MPEG-2 Compression | Achieves substantial reduction in storage and bandwidth requirements for audiovisual content; without it digital media would not be practical. Defines a framework for organizing program information. |
Does not work well for all video content; tradeoffs in visual quality are required.
Makes networking more complex; requires integration with networking. Imposes delays. |
| MPEG-4 Compression |
Achieves substantial reduction in storage and bandwidth requirements for audiovisual content.
Supports interactivity by allowing users to interact with objects rather than pixels. Leverages Quicktime file format. Would enable HDTV to coexist with other services on the same channel. | Requires substantial computer power in the receiver. Uses standards that are not completed. |